Hyeonjoon Shin

N=(4,4) Type IIA String Theory on PP-Wave Background

We construct IIA GS superstring action on the ten-dimensional pp-wave background, which arises as the compactification of eleven-dimensional pp-wave geometry along the isometry direction. The background geometry has 24 Killing spinors and among them, 16 components correspond to the non-linearly realized kinematical supersymmetry in the string action. The remaining eight components are linearly realized and shown to be independent of x^+ coordinate, which is identified with the world-sheet time coordinate of the string action in the light-cone gauge. The resultant dynamical N=(4,4) supersymmetry is investigated, which is shown to be consistent with the field contents of the action containing two free massive supermultiplets.

Branes from matrix theory in pp-wave background

Based on the recently proposed action for matrix theory describing the DLCQ M-theory in the maximally supersymmetric pp-wave background, we obtain the supersymmetry algebra of supercharge density. Using supersymmetry transformation rules for fermions, we identify BPS states with the central charges in the supersymmetry algebra, which can be activated only in the large-N limit. They preserve some fraction of supersymmetries and correspond to rotating transverse membranes and longitudinal fivebranes.

Solvable N=(4,4) type IIA string theory in plane-wave background and D-branes

Abstract We study various aspects of N =(4,4) type IIA GS superstring theory in the pp-wave background, which arises as the compactification of maximally supersymmetric eleven-dimensional pp-wave geometry along the spacelike isometry direction. We show the supersymmetry algebra of N =(4,4) worldsheet supersymmetry as well as non-linearly realized supersymmetry. We also give quantization of closed string and open string incorporating various boundary conditions. From the open string boundary conditions, we find configurations of D-branes which preserve half the supersymmetries. Among these we identify D4-brane configurations with longitudinal five-brane configurations in matrix model on the eleven-dimensional pp-wave geometry.

Covariant description of D-branes in IIA plane-wave background

We work out boundary conditions for the covariant open string in the type IIA plane wave background, which corresponds to the D-branes in the type IIA theory. We use the kappa symmetric string action and see what kind of boundary conditions should be imposed to retain kappa symmetry. We find half BPS as well as quarter BPS branes and the analysis agrees with the previous work in the light cone gauge if the result is available. Finally we find that D0-brane is non-supersymmetric.

One-loop flatness of membrane fuzzy sphere interaction in plane-wave matrix model

Abstract In the plane-wave matrix model, the background configuration of two membrane fuzzy spheres, one of which rotates around the other one in the SO (6) symmetric space, is allowed as a classical solution. We study the one-loop quantum corrections to this background in the path integral formulation. Firstly, we show that each fuzzy sphere is stable under the quantum correction. Secondly, the effective potential describing the interaction between fuzzy spheres is obtained as a function of r , which is the distance between two fuzzy spheres. It is shown that the effective potential is flat and hence the fuzzy spheres do not feel any force. The possibility on the existence of flat directions is discussed.

Thermodynamics of fuzzy spheres in pp-wave matrix model

Abstract We discuss thermodynamics of fuzzy spheres in a matrix model on a pp-wave background. The exact free energy in the fuzzy sphere vacuum is computed in the μ → ∞ limit for an arbitrary matrix size N. The trivial vacuum dominates the fuzzy sphere vacuum at low temperature while the fuzzy sphere vacuum is more stable than the trivial vacuum at sufficiently high temperature. Our result supports that the fluctuations around the trivial vacuum would condense to form an irreducible fuzzy sphere above a certain temperature.

Renormalized Entanglement Entropy Flow in Mass-deformed ABJM Theory

We investigate a mass deformation effect on the renormalized entanglement entropy (REE) near the UV fixed point in (2+1)-dimensional field theory. In the context of the gauge/gravity duality, we use the Lin-Lunin-Maldacena (LLM) geometries corresponding to the vacua of the mass-deformed ABJM theory. We analytically compute the small mass effect for various droplet configurations and show in holographic point of view that the REE is monotonically decreasing, positive, and stationary at the UV fixed point. These properties of the REE in (2+1)-dimensions are consistent with the Zamolodchikov

Anomaly and Hawking Radiation from Regular Black Holes

c

Membrane fuzzy sphere dynamics in plane-wave matrix model

-function proposed in (1+1)-dimensional conformal field theory.

Infinite Lorentz boost along theM-theory circle and nonasymptotically flat solutions in supergravities

We consider the Hawking radiation from two regular black holes, the minimal model and the noncommutative black hole. The flux of Hawking radiation is derived by applying the anomaly cancellation method proposed by Robinson and Wilczek. Two regular black holes have the same radiation pattern except for the detailed expression for the Hawking temperature. The resulting flux of the energy-momentum tensor is shown to be precisely the same as the thermal flux from each regular black hole at the Hawking temperature.